measuring allocation errors in land change models in amazonia
Post on 06-Feb-2016
24 Views
Preview:
DESCRIPTION
TRANSCRIPT
Measuring Allocation Errors in Land Change Models in Amazonia
Luiz Diniz, Merret Buurman, Pedro Andrade, Gilberto Câmara, Edzer Pebesma
Merret BuurmanGeoInfo, Campos do Jordão, 25 November 2013
Luiz Diniz Merret Buurman Pedro Andrade Gilberto Câmara Edzer Pebesma
+
Measuring Allocation Errors in Land Change Models in Amazonia
& 3
Merret Buurman, 26.11.2013
„Why?“
& 4
Merret Buurman, 26.11.2013
Land change modellingSimulation
Observed reality2001
2002
2003
2004
& 5
Merret Buurman, 26.11.2013
Land change modelling
Big responsabilityNeed to evaluate resultsThis can only be done afterwards!
2004
& 6
Merret Buurman, 26.11.2013
(1) Goodness of fit metric
(2) Evaluation of models
& 7
Merret Buurman, 26.11.2013
(1) Goodness of fit metric
& 8
Merret Buurman, 26.11.2013
Two complementary views…
Costanza:Multiple
resolutions
Pontius et al.:Need to consider
persistence
Pontius Jr, R.G., E. Shusas, and M. McEachern, Detecting important categoricalland changes while accounting for persistence. Agriculture, Ecosystems &Environment, 2004. 101(2): p. 251-268.
Costanza, R., Model Goodness of Fit - a Multiple Resolution Procedure.Ecological Modelling, 1989. 47(3-4): p. 199-215.
& 9
Merret Buurman, 26.11.2013
Two complementary views…
Costanza:Multiple
resolutions
Pontius et al.:Need to consider
persistence
Pontius Jr, R.G., E. Shusas, and M. McEachern, Detecting important categoricalland changes while accounting for persistence. Agriculture, Ecosystems &Environment, 2004. 101(2): p. 251-268.
Costanza, R., Model Goodness of Fit - a Multiple Resolution Procedure.Ecological Modelling, 1989. 47(3-4): p. 199-215.
& 10
Merret Buurman, 26.11.2013
Multiple resolutions
& 11
Merret Buurman, 26.11.2013
Multiple resolutions
& 12
Merret Buurman, 26.11.2013
Multiple resolutions
& 13
Merret Buurman, 26.11.2013
Multiple resolutions
& 14
Merret Buurman, 26.11.2013
Multiple resolutions
& 15
Merret Buurman, 26.11.2013
Multiple resolutions
& 16
Merret Buurman, 26.11.2013
Multiple resolutions
& 17
Merret Buurman, 26.11.2013
Multiple resolutions
& 18
Merret Buurman, 26.11.2013
Two complementary views…
Costanza:Multiple
resolutions
Pontius et al.:Need to consider
persistence
& 19
Merret Buurman, 26.11.2013
Two complementary views…
Costanza:Multiple
resolutions
Pontius et al.:Need to consider
persistence
& 20
Merret Buurman, 26.11.2013
Need to consider persistence
• Many cases: Most of the area does not change• Focus: Predicting the changed area
Example:• 99% of the area unchanged• All the change predicted at wrong locations• 98 % of the area is „correct“!
& 21
Merret Buurman, 26.11.2013
… Combined into one
Change-focusing multiple-resolution
goodness of fit
& 22
Merret Buurman, 26.11.2013
What do we evaluate?
& 23
Merret Buurman, 26.11.2013
What do we evaluate?
& 24
Merret Buurman, 26.11.2013
What do we evaluate?
Equal total amount!
& 25
Merret Buurman, 26.11.2013
Goodness of fit metric
• (1) Inside sampling window: Compute the difference in amount of change between both grids
& 26
Merret Buurman, 26.11.2013
Goodness of fit metric
• (2) Sum this up for all sampling windows
& 27
Merret Buurman, 26.11.2013
Goodness of fit metric
• (3) Divide by twice the total amount of change– Why twice? In the previous steps, every „wrong“
allocation was counted twice, because too much change in one cell automatically means too little change in another, due to the equality of demand in both grids.
& 28
Merret Buurman, 26.11.2013
Goodness of fit metric
• (4) Subtract from one to get goodness
• … and repeat for all other resolutions
& 29
Merret Buurman, 26.11.2013
Goodness of fit metric
• Fw = Goodness of fit at resolution w.
• tw = Number of sampling windows at resolution w.• w = Resolution (a sampling window has w2 cells).• arefi = Percent of change in land cover in cell i in the reference cell space.
• amodj = Change in land use/land cover in cell j in the model cell space.• i, j = Cells inside a sampling window.• u = Cells inside the cell space.• s = A sampling window.• num = Number of cells in the cell space (tw * w2)
& 30
Merret Buurman, 26.11.2013
(2) Evaluation of models
& 31
Merret Buurman, 26.11.2013
Models
SimAmazonia 2001 2050
BAU and GOVSoares-Filho, B., et al., Modelling conservation in the Amazon basin. Nature, 2006. 440(7083): p. 520-523.
& 32
Merret Buurman, 26.11.2013
Models
SimAmazonia 2001 2050
BAU and GOVSoares-Filho, B., et al., Modelling conservation in the Amazon basin. Nature, 2006. 440(7083): p. 520-523.
Laurance 2000 2020Optimistic Non-Opt.
Laurance, W., et al., The future of the Brazilian Amazon. Science, 2001. 291: p.438-439.
Compare with PRODES 2011 (25x25km)
& 33
Merret Buurman, 26.11.2013
& 34
Merret Buurman, 26.11.2013
& 35
Merret Buurman, 26.11.2013
Why so weak?
• Neighborhood model: captures only existing regions (not new frontiers)
• Similarity Neighborhood model & SimAmazonia: Same reason? Compare maps!
& 36
Merret Buurman, 26.11.2013
& 37
Merret Buurman, 26.11.2013
Why so weak?
• Neighborhood model: captures only existing regions (not new frontiers)
• Similarity Neighborhood model & SimAmazonia: Same reason? Compare maps!
• Yes! Location of new frontiers difficult to predict
& 38
Merret Buurman, 26.11.2013
Why so weak?
• Laurance• Overestimates roads• Assumes same impact of roads everywhere• Underestimates protected areas
& 39
Merret Buurman, 26.11.2013
Indigenous areas (FUNAI)
Parquedo Xingu
& 40
Merret Buurman, 26.11.2013
Conclusion
• Predicting the locations of future deforestation:More difficult than expected!
• Problem: Policy recommendation based on those predictions
• Our hope: Next generation of deforestation models will capture better the complex human decision-making
& 41
Merret Buurman, 26.11.2013
Conclusion
• Predicting the locations of future deforestation:More difficult than expected!
• Problem: Policy recommendation based on those predictions
• Our hope: Next generation of deforestation models will capture better the complex human decision-making
Obrigada!
top related